A unitary stratified composite composed of a first stratum and a second stratum integrally connected by a transition zone is disclosed. The method for surface treatment includes a step of subjecting a surface of a base plate having at least two kinds of substrate patterns formed thereon to a surface treatment for forming a self-assembled monomolecular layer for at least once and a surface treatment by ultraviolet-ozone cleaning, so as to make the difference between the surface energies of the substrate patterns larger or smaller. The present invention may meet the requirement for the position precision between the valve body and the end cover and improve the welding precision therebetween. The isolated layer of the substrate has a thickness that is less than the thickness at which defects are caused in the crystalline lattice of the first material by the second material crystallizing thereon. An establishing unit establishes an overlap region between the first and second projection areas as the no-entry zone for the robot. Because of this collection of disturbance variables, at least a control variable is automatically changed in order to compensate or to diminish the influence of the disturbance variable on the welding seam quality.